/*
 * This is an OpenSSL-compatible implementation of the RSA Data Security, Inc.
 * MD4 Message-Digest Algorithm (RFC 1320).
 *
 * Homepage:
 * http://openwall.info/wiki/people/solar/software/public-domain-source-code/md4
 *
 * Author:
 * Alexander Peslyak, better known as Solar Designer <solar at openwall.com>
 *
 * This software was written by Alexander Peslyak in 2001.  No copyright is
 * claimed, and the software is hereby placed in the public domain.
 * In case this attempt to disclaim copyright and place the software in the
 * public domain is deemed null and void, then the software is
 * Copyright (c) 2001 Alexander Peslyak and it is hereby released to the
 * general public under the following terms:
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted.
 *
 * There's ABSOLUTELY NO WARRANTY, express or implied.
 *
 * (This is a heavily cut-down "BSD license".)
 *
 * This differs from Colin Plumb's older public domain implementation in that
 * no exactly 32-bit integer data type is required (any 32-bit or wider
 * unsigned integer data type will do), there's no compile-time endianness
 * configuration, and the function prototypes match OpenSSL's.  No code from
 * Colin Plumb's implementation has been reused; this comment merely compares
 * the properties of the two independent implementations.
 *
 * The primary goals of this implementation are portability and ease of use.
 * It is meant to be fast, but not as fast as possible.  Some known
 * optimizations are not included to reduce source code size and avoid
 * compile-time configuration.
 */

#ifndef HAVE_OPENSSL

#include <string.h>

#include "md4.h"

/*
 * The basic MD4 functions.
 *
 * F and G are optimized compared to their RFC 1320 definitions, with the
 * optimization for F borrowed from Colin Plumb's MD5 implementation.
 */
#define F(x, y, z)          ((z) ^ ((x) & ((y) ^ (z))))
#define G(x, y, z)          (((x) & ((y) | (z))) | ((y) & (z)))
#define H(x, y, z)          ((x) ^ (y) ^ (z))

/*
 * The MD4 transformation for all three rounds.
 */
#define STEP(f, a, b, c, d, x, s) \
    (a) += f((b), (c), (d)) + (x); \
    (a) = (((a) << (s)) | (((a) & 0xffffffff) >> (32 - (s))));

/*
 * SET reads 4 input bytes in little-endian byte order and stores them
 * in a properly aligned word in host byte order.
 *
 * The check for little-endian architectures that tolerate unaligned
 * memory accesses is just an optimization.  Nothing will break if it
 * doesn't work.
 */
#if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
#define SET(n) \
    (*(MD4_u32plus *)&ptr[(n) * 4])
#define GET(n) \
    SET(n)
#else
#define SET(n) \
    (ctx->block[(n)] = \
    (MD4_u32plus)ptr[(n) * 4] | \
    ((MD4_u32plus)ptr[(n) * 4 + 1] << 8) | \
    ((MD4_u32plus)ptr[(n) * 4 + 2] << 16) | \
    ((MD4_u32plus)ptr[(n) * 4 + 3] << 24))
#define GET(n) \
    (ctx->block[(n)])
#endif

/*
 * This processes one or more 64-byte data blocks, but does NOT update
 * the bit counters.  There are no alignment requirements.
 */
static const void *body(MD4_CTX *ctx, const void *data, unsigned long size)
{
    const unsigned char *ptr;
    MD4_u32plus a, b, c, d;
    MD4_u32plus saved_a, saved_b, saved_c, saved_d;

    ptr = (const unsigned char *)data;

    a = ctx->a;
    b = ctx->b;
    c = ctx->c;
    d = ctx->d;

    do
    {
        saved_a = a;
        saved_b = b;
        saved_c = c;
        saved_d = d;

        /* Round 1 */
        STEP(F, a, b, c, d, SET(0), 3)
        STEP(F, d, a, b, c, SET(1), 7)
        STEP(F, c, d, a, b, SET(2), 11)
        STEP(F, b, c, d, a, SET(3), 19)
        STEP(F, a, b, c, d, SET(4), 3)
        STEP(F, d, a, b, c, SET(5), 7)
        STEP(F, c, d, a, b, SET(6), 11)
        STEP(F, b, c, d, a, SET(7), 19)
        STEP(F, a, b, c, d, SET(8), 3)
        STEP(F, d, a, b, c, SET(9), 7)
        STEP(F, c, d, a, b, SET(10), 11)
        STEP(F, b, c, d, a, SET(11), 19)
        STEP(F, a, b, c, d, SET(12), 3)
        STEP(F, d, a, b, c, SET(13), 7)
        STEP(F, c, d, a, b, SET(14), 11)
        STEP(F, b, c, d, a, SET(15), 19)

        /* Round 2 */
        STEP(G, a, b, c, d, GET(0) + 0x5a827999, 3)
        STEP(G, d, a, b, c, GET(4) + 0x5a827999, 5)
        STEP(G, c, d, a, b, GET(8) + 0x5a827999, 9)
        STEP(G, b, c, d, a, GET(12) + 0x5a827999, 13)
        STEP(G, a, b, c, d, GET(1) + 0x5a827999, 3)
        STEP(G, d, a, b, c, GET(5) + 0x5a827999, 5)
        STEP(G, c, d, a, b, GET(9) + 0x5a827999, 9)
        STEP(G, b, c, d, a, GET(13) + 0x5a827999, 13)
        STEP(G, a, b, c, d, GET(2) + 0x5a827999, 3)
        STEP(G, d, a, b, c, GET(6) + 0x5a827999, 5)
        STEP(G, c, d, a, b, GET(10) + 0x5a827999, 9)
        STEP(G, b, c, d, a, GET(14) + 0x5a827999, 13)
        STEP(G, a, b, c, d, GET(3) + 0x5a827999, 3)
        STEP(G, d, a, b, c, GET(7) + 0x5a827999, 5)
        STEP(G, c, d, a, b, GET(11) + 0x5a827999, 9)
        STEP(G, b, c, d, a, GET(15) + 0x5a827999, 13)

        /* Round 3 */
        STEP(H, a, b, c, d, GET(0) + 0x6ed9eba1, 3)
        STEP(H, d, a, b, c, GET(8) + 0x6ed9eba1, 9)
        STEP(H, c, d, a, b, GET(4) + 0x6ed9eba1, 11)
        STEP(H, b, c, d, a, GET(12) + 0x6ed9eba1, 15)
        STEP(H, a, b, c, d, GET(2) + 0x6ed9eba1, 3)
        STEP(H, d, a, b, c, GET(10) + 0x6ed9eba1, 9)
        STEP(H, c, d, a, b, GET(6) + 0x6ed9eba1, 11)
        STEP(H, b, c, d, a, GET(14) + 0x6ed9eba1, 15)
        STEP(H, a, b, c, d, GET(1) + 0x6ed9eba1, 3)
        STEP(H, d, a, b, c, GET(9) + 0x6ed9eba1, 9)
        STEP(H, c, d, a, b, GET(5) + 0x6ed9eba1, 11)
        STEP(H, b, c, d, a, GET(13) + 0x6ed9eba1, 15)
        STEP(H, a, b, c, d, GET(3) + 0x6ed9eba1, 3)
        STEP(H, d, a, b, c, GET(11) + 0x6ed9eba1, 9)
        STEP(H, c, d, a, b, GET(7) + 0x6ed9eba1, 11)
        STEP(H, b, c, d, a, GET(15) + 0x6ed9eba1, 15)

        a += saved_a;
        b += saved_b;
        c += saved_c;
        d += saved_d;

        ptr += 64;
    }
    while (size -= 64);

    ctx->a = a;
    ctx->b = b;
    ctx->c = c;
    ctx->d = d;

    return ptr;
}

void MD4_Init(MD4_CTX *ctx)
{
    ctx->a = 0x67452301;
    ctx->b = 0xefcdab89;
    ctx->c = 0x98badcfe;
    ctx->d = 0x10325476;

    ctx->lo = 0;
    ctx->hi = 0;
}

void MD4_Update(MD4_CTX *ctx, const void *data, unsigned long size)
{
    MD4_u32plus saved_lo;
    unsigned long used, available;

    saved_lo = ctx->lo;
    if ((ctx->lo = (saved_lo + size) & 0x1fffffff) < saved_lo)
        ctx->hi++;
    ctx->hi += size >> 29;

    used = saved_lo & 0x3f;

    if (used)
    {
        available = 64 - used;

        if (size < available)
        {
            memcpy(&ctx->buffer[used], data, size);
            return;
        }

        memcpy(&ctx->buffer[used], data, available);
        data = (const unsigned char *)data + available;
        size -= available;
        body(ctx, ctx->buffer, 64);
    }

    if (size >= 64)
    {
        data = body(ctx, data, size & ~(unsigned long)0x3f);
        size &= 0x3f;
    }

    memcpy(ctx->buffer, data, size);
}

void MD4_Final(unsigned char *result, MD4_CTX *ctx)
{
    unsigned long used, available;

    used = ctx->lo & 0x3f;

    ctx->buffer[used++] = 0x80;

    available = 64 - used;

    if (available < 8)
    {
        memset(&ctx->buffer[used], 0, available);
        body(ctx, ctx->buffer, 64);
        used = 0;
        available = 64;
    }

    memset(&ctx->buffer[used], 0, available - 8);

    ctx->lo <<= 3;
    ctx->buffer[56] = ctx->lo;
    ctx->buffer[57] = ctx->lo >> 8;
    ctx->buffer[58] = ctx->lo >> 16;
    ctx->buffer[59] = ctx->lo >> 24;
    ctx->buffer[60] = ctx->hi;
    ctx->buffer[61] = ctx->hi >> 8;
    ctx->buffer[62] = ctx->hi >> 16;
    ctx->buffer[63] = ctx->hi >> 24;

    body(ctx, ctx->buffer, 64);

    result[0] = ctx->a;
    result[1] = ctx->a >> 8;
    result[2] = ctx->a >> 16;
    result[3] = ctx->a >> 24;
    result[4] = ctx->b;
    result[5] = ctx->b >> 8;
    result[6] = ctx->b >> 16;
    result[7] = ctx->b >> 24;
    result[8] = ctx->c;
    result[9] = ctx->c >> 8;
    result[10] = ctx->c >> 16;
    result[11] = ctx->c >> 24;
    result[12] = ctx->d;
    result[13] = ctx->d >> 8;
    result[14] = ctx->d >> 16;
    result[15] = ctx->d >> 24;

    memset(ctx, 0, sizeof(*ctx));
}

#endif
